Effects of spirulina (Arthrospira platensis) as a fishmeal replacer in practical diets on growth performance, proximate composition, and amino acids profile of pabda catfish (Ompok pabda)

Spirulina, Arthrospira platensis (SP), is a filamentous blue-green alga with high nutritional value that makes it a promising component for fish meal (FM) replacement in aqua feeds. With this perspective, the current feeding trial was carried out to find out the effects of inclusion of SP protein instead of FM protein on the growth, carcass composition, and amino acids profile of muscles of pabda catfish, Ompok pabda. The current study was carried out in earthen pits (sized 0.64 m(3)) at a stocking density of 40 fish/pit. Five experimental diets-S-0 (control), S-10, S-15, S-20, and S-25-were prepared by replacing 0%, 10%, 15%, 20%, and 25% FM protein with SP protein respectively in triplicates. Fish were fed manually with the experimental diets thrice a day up to satiation level for 8 weeks. The higher growth performance of pabda catfish was significantly (P < 0.05) observed for the SP-containing diets than for the control diet. In terms of weight gain, weight gain percent, and specific growth rate, the S-15 diet showed the optimum performance. Feed intake in this fish group was higher than the control diet, but no significant (P > 0.05) changes were observed in feed conversion value and protein efficiency ratio; their ranges were 1.57-1.60 and 1.79-1.82 respectively. High ash content and low lipids contents were found in fish fed with SP-treated diets compared to the control group. Most essential and nonessential amino acids significantly (P < 0.05) increased with increasing SP levels in the diets. From these results, it is concluded that FM protein replaced by SP protein at the 15% level showed the optimum performance with better muscles quality of pabda catfish, O. pabda.